Mast sheaves wont turn......

May have been mentioned earlier.
A source of steam will help loosen all the crud. I used a wall paper steamer and went off and had a cup of tea. Watch out that you do not damage any plastic in the actual pulley bit.

Then of course a liberal dose of WD40 or similar and a large hammer and a drift to encourage the pin out.

Waterproof grease tends to be useful when the whole thing is put together again
 
Lidl sell a de-scaler that is powerful and effective - cheap too. Have a bottle in the bilges somewhere. Works a treat on cleaning up the heat exchanger too!
 
Did mine last year,remember to run a line or place something underneath the sheaves before tapping the shafts out if there is any possibility the sheaves could slide into the mast. My sheaves were worn and needed replacing.Incidentally I replaced the aluminium sheaves with tufnol ones.They are working fine.
Good luck
Harry.
 
Thanks everyone, some of you have missed the fact that the pin is not visible and there is no access to the pin. I've assumed the pin is in cast aluminium lugs going down into the mast, and the top is then welded to the mast. I'll certainly try boiling water and then WD40( or the other product mentioned ACF 50). I'll have to wait until the weather improves though!
Thanks again everyone.
 
M33 said:
Thanks everyone, some of you have missed the fact that the pin is not visible and there is no access to the pin. I've assumed the pin is in cast aluminium lugs going down into the mast, and the top is then welded to the mast. I'll certainly try boiling water and then WD40( or the other product mentioned ACF 50). I'll have to wait until the weather improves though!
Thanks again everyone.
Click to expand...

What mast is it
 
Invisible pin

I had a similar problem on my mast.

I found that the axle pin was actually welded onto an oblong shaped cover plate fastened on the side wall of the mast by two small self tapping screws.

Heres hoping you have a similar set up.

I would be surprised if you have a welded sheave assembly that does not allow for access and sheave replacement without drilling the side wall.

Incidentally my axle pin was also badly corroded in place. So it had to be eased out with a combination of hot water, plus gas penetrating oil and a twisting and levering action on the end plate.

As other posters have said previously make sure you take precautions to make sure the sheaves and nylon bushes dont drop into the mast whilst you are pulling the axle pin out. I packed them out with thin strips of steel like feeler guages to make sure.

hoping this may help.
 
M33 said:
Thanks everyone, some of you have missed the fact that the pin is not visible and there is no access to the pin. I've assumed the pin is in cast aluminium lugs going down into the mast, and the top is then welded to the mast.
Click to expand...

My mast is around the same age. Due to the sheaves having seized on the pins, the pins had been turning within the mast crane and had worn the mounting holes oval. I removed the mast crane, re-bored the holes and fitted oversize pins with larger ID sheaves. But if your mast crane is welded in position.........
 
If its like these http://www.seldenmast.co.uk/fittings/listing.asp?Category_ID=3 you'd have to remove the sheave box from the mast (could be rivetted or self tappers) before you can remove the sheave. Not too difficult. The axle is generally removed by tapping out using a suitable drift (an old drill bit is good but use the blunt end). Once its removed you can thoroughly clean and replace the sheave if necessary. No lubrication is necessary.
 
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